"Thorsten Ottosen" <tottosen@dezide.com> wrote in message news:<dpmc2d$f75$1@sea.gmane.org>...

David Maisonave wrote:

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"Thorsten Ottosen" <tottosen@dezide.com> wrote in message

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I'm not sure I fully understand how the detection mechanism would work in your cow_ptr.

Example code: template<typename T_obj> cow_ptr(T_obj* type): m_ref_count(new ref_count(type, get_alloc_func(type))) { assert(typeid(*type) == typeid(T_obj)); }

how can that assertion ever fail when T_obj is deduced?

The only way that cow_ptr and copy_ptr can get slice is if the wrong type is pass to the constructor. Example code: Derivedtype* p = new DerivedDerivedType; cow_ptr<BaseType> pBase(p); //This will cause an assertion since p type does not match the pointee

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Since the cow_ptr works by capturing the type on the constructor, it

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can easily determine if the right type is being passed in, and if it

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matches the pointee type. That can't be done with the boost pointer containers because they don't catch the type on the constructor, nor

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is it part of the required logic for using a clone function method.

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Nevertheless, as soon as the object is outside a cow_ptr might be sliced. That's reason enough not to allow it.

I'm not sure what you're referring to here. Can you post an example?

*ptr = *ptr2;

Can you please give a more complete example? Which is the smart pointer, here, and exactly what type of pointers?